The invention relates generally to two-stroke internal combustion engines, and more particularly, to fuel supply arrangements for such engines.
One prior two-stroke engine used in boat racing employed a fuel injector which was located in an air intake passage communicating through reed valve means with a two stroke engine crankcase and which supplied the engine with fuel mixed with oil. The inlet passage included a throttle valve upstream of the fuel injector.
Another prior two-stroke engine employed a fuel injector which was located in a transfer passage between a crankcase chamber and the combustion chamber and which supplied fuel unmixed with oil.
Attention is directed to Haman U.S. Pat. No. 4,462,346 which discloses fuel supply through the crankcase at high speeds and fuel supply through a port in a transfer passage, independently of the crankcase, at slow speeds. However, both supplies are provided by orifices which are subject to vacuum and do not involve fuel injection. In addition, both supplies use the same fuel or fuel mixture.
Attention is also directed to the following U.S patents: